Aerobic training is the foundation of all cross country programs. The length of the race dictates the energy demand required, and the intensity of the effort establishes the proportion of aerobic to anaerobic energy system contribution. All cross country races of two miles or longer have a greater than 90% aerobic contribution at full effort. There are many key workouts that develop an efficient and robust aerobic energy system in the body, especially the long run. Just going out for a jog will help develop the aerobic system up to a point. The volume of miles run during a macrocycle plays a huge role in developing the aerobic base. However, to fully develop the aerobic system in the least amount of time, more than just total volume of miles must be considered.
The aerobic energy system becomes more efficient and robust with training efforts done at VO2 max pace and slower. Workouts done at both the lactate threshold (tempo runs) and the aerobic threshold are valuable training tools in building the aerobic foundation. The same base-building runs done early in the season become the recovery runs later in the season. All of this work has one characteristic in common: limited lactate build-up during the work and almost no acidosis that requires more than 24 hours to recover from.
The long run is both an important physiological concept and a training tool for the cross country coach. The reasons to have a long run in every training microcycle have to do with strengthening and adapting the aerobic energy system in the most effective way.
Adaptations resulting from the long run training stimulus occur in the aerobic system because of changes in the:
- 1. Cardiovascular System
- 2. Muscular System
- 3. Aerobic Metabolism
Adaptations occur as follows:
- Increased heart volume
- Decreased resting heart rate (HR)
- Increased stroke volume in left ventricle (SV)
- Increased Cardiac Output (Q = HR x SV)
- Increased blood flow to working muscles
- Increased blood volume and red blood cell composition
- Increased slow twitch muscle fiber recruitment
- Increased oxidative fast twitch muscle fiber recruitment
- Increased capillarization at the muscle fiber
- Increased mitochondria characteristics i.e. type, size, and number
- Increased oxygen extraction (avO2 difference) due to enzyme increases
- Increase in levels of myoglobin in the muscle fiber
- Increased efficiency in fatty acid storage exchange and use as substrate
- Increased efficiency in glycogen storage exchange and use as substrate
The training regimes for the long run have been established by exercise physiologists through the scientific method and validated through the peer-review process. The main focus is a continuous run that is at the extreme outer edge of a runner’s aerobic fitness capability.
Long continuous runs, other than recovery runs, that are run at or below 70% of VO2 Max (approximately 130-140 beats per minute) will bring about significant aerobic adaptations if done properly. The use of fatty acids as the primary substrate will spare glycogen for use at faster running speeds during later workouts in the microcycle. The nature of this type of continuous running emphasizes volume at appropriate intensities to keep the heart rate within the 130-140 bpm range for an extended period of time. The greater the volume of training a runner can handle, the more adaptations to training that may potentially occur. Additionally, the longer that this type of training can be applied, the more the adaptations that will occur at the specific training regimes for the various endurance events.
The volume of the long run will be determined by the athlete’s training age, fitness levels, and the willingness to do this type of work. As a general rule, training at or below 70% of the individuals specificVO2 Max pace must be from one to three hours of continuous running.
Training Parameters of the Long Run
- Run at a heart rate of 130-140 bpm
- Fatty acids are the primary fuel source
- Volume of single run is 20% of present weekly mileage
- 1 to 3 hours in duration
- Intensity is 70% of field-tested VO2 Max pace
- 24-36 hours recovery time
- Too fast or too long beyond guidelines skews the recovery
The cross country coach must resist the notion that this workout is just a long social run. VO2 Max pace is very individual specific and only those within the same pace range should run this far together. The aerobic threshold is marked by what some call “gossip pace”, but only for those of nearly the same ability. Some experienced athletes regard 70% of date VO2 max pace as too slow to run the long run. Please be aware that the athlete certainly has the ability to run it faster. However the training adaptations that are expected do not change by an increase in intensity. Save that work for the tempo runs near lactate threshold at a later. Running too fast simply changes the recovery schedule and nothing else.
Scott Christensen is the head track coach at Stillwater Area High School in Oak Park Heights, MN.